Hatchback, and everybody else
I looked at eye cups on eBay and there are quite a number that might be usable, but if I was going to use one the camera would not fit into the camera bag.
The basic problem is that I wear glasses, so that quite a lot of light gets into the EVF to make it unusable, at least for me.
My solution is to take the glasses off, adjust the diopter focus, and shoot. It allows my eyes to get close enough to seal the EVF against outside light, and under these conditions the brightness of the EVF is just adequate.
Fortunately my vision is such that I can walk around w/o glasses w/o breaking my neck so this is a viable solution for the outdoors. And as others have mentioned it enhances the stability of the video.
This may also explain why there have been so few complaints about the low brightness.
In overcast conditions I still use the regular display, in the HI brightness mode, holding the camera with both hands.
We are taking a trip to Catalina Island next month, should produce some great shots.
We all need a TV to display the gorgeous video the AX100 produces, my TV is a back lit Vizio with close to 1000 led's, great picture. Vizio showed a 4K P series at the CES very attractive pricing and PQ that got rave reviews, here is their ad, very detailed, you may have to click and scroll to get it going. It is the 70" that I am looking forward to see, supposedly under $ 2500.00 !.